How to Prevent Tree Roots from Growing Into Your Pipes

Trees are an important asset to your home, both for aesthetics and for a positive impact on property value. Tree and some shrub roots can become problematic if they are close to your sewer line. They are attracted to the waste pipe that runs from your house to the street or out to the septic tank in the back yard.

A sewer pipe contains water, nutrients and oxygen – all vital to the growth of a tree. Roots are on a mission to find these three nutritional elements. If you have trees anywhere near the line, roots will likely grow toward them.

Wastepipe materials have changed over the years. Your house may be fairly modern or totally renovated but have clay or cast iron pipe to carry away waste. These pipes are known to crack or corrode in places. Even plastic pipes can crack from seismic shifts or excavation accidents.

If the breach is small, it goes unnoticed. However, these openings become an entry point for tree roots. Once roots enter the pipe, they grow rapidly, expanding the hole and clogging the natural flow of waste to the main municipal sewer line. Eventually you have a sewer clog that backs up into your toilets and tubs. Not fun.

Here’s how to help prevent the problem, assuming you do not already have a root clog in your sewer line or a problem that could require sewer replacement.

Find Your Sewer Line

Per building code, your home should have a clean out in two locations: one outside the foundation wall and one within four yards of the street curb. Each clean out has a cap on top that looks like circle with a square in the middle (for an open ended wrench). If you can’t find them, they may be buried by the landscaping. Some older houses or houses where the plumbing was not entirely built to spec may not have these clean outs.

If you find the caps, you can assume that the sewer pipe lays in a straight line between the two caps. If you can’t find them, call your local water department and have them mark where your pipes connect to the municipal sewer.

Find the Trees

This part is easy. Do you have a tree or trees or strong-root bushes or hedges near this sewer line? Are the trees well established? Young trees and saplings are not generally a problem.

Many trees are planted with care away from the foundation walls to avoid cracking these walls when, years later, they are mature and more spread out. Often, although they are away from the house they are planted out on the front lawn where they can be viewed from the living room window. This often places them dangerously near the sewer line.

Inspect the Sewer Line

If you’ve had no problems with your sewer, you might be reluctant to have a professional sewer inspection at this point. Some homeowners wait until they experience signs of trouble.

  • More than one toilet backed up at the same time. This indicates a sewer line clog. It could be an internal clog or a root clog.
  • Sewer odors in the front yard. Cracks or leaks in the pipe can saturate the ground under the lawn, creating a stinky odor.
  • Sunken areas of the lawn. Pipe breaks can be eroding the earth alongside the pipe toward the street.

The problem with waiting is that you are actually holding back until a situation becomes urgent and potentially more expensive. Our technicians at Benjamin Franklin Plumbing in the Bay Area recommend a professional sewer line inspection if:

  • Your house was built more than 15 years ago and has not recently had an inspection.
  • Mature trees are within the proximity of your sewer line.
  • You suspect, based on other houses in the neighborhood, that your sewer line pipes are based on older material such as clay or iron.
  • Your neighbors with similar houses have had trouble with their sewer lines.

Our team is experienced in sewer line inspections throughout the Bay Area. We know the soil and geographical characteristics of each region. We understand how and when trees become problems for pipes, and we have an extensive multi-point list we run through to isolate problems.

We will run a video camera down your pipe to actually see inside the line and inspect the integrity of the pipe walls every foot of the way. If there are roots breaking in or already established, we’ll find them. Handling a roots issue at this point is much less expensive. Rather than dealing with a sudden problem, you keep the flows of your home operating as they should, problem-free, by addressing the issue early.

Root Removal and Repair

If roots have been found in your pipe there are several solutions.

  • Run a power auger down through the roots, cutting them up and flushing them down into the main sewer.
  • Kill the roots with herbicides that cling to the breach to prevent new root growth in that area. Note that this doesn’t damage the tree. It only causes the spread of roots to reroute away from the pipe crack. This is a temporary solution but can last for several years. Many of us prefer to avoid the use of herbicides, for good reason, and this may not be the optimal solution for a root problem.
  • If the root damage is severe (breaches in several places) or there are collapsed sections, it may be necessary to replace the entire sewer line. The good news is that technology has evolved and a new “trenchless sewer line” can be run without digging up the yard. There are several ways to do this, but the end product really seals the line against the incursion of roots.
  • Remove or relocate the tree. While this is often unthinkable if the tree is well established and attractive, it may be that the tree has grown too large for its space and also threatens the foundation walls, hard landscape and/or roof. Removing the tree offers an opportunity to re-landscape and plant smaller trees in more strategic locations. Some homeowners have even used the lumber to create outdoor furniture or otherwise recycled the material. In most cases, it will be better to install a new trenchless sewer line.


You may be required to obtain a permit before you can remove a tree. In some locations, you may be required to plant another tree.